A text subtitle display is a technique for displaying subtitles represented by text codes, in synchronization with each picture of a motion picture. This is one of techniques unique to BD-ROM (Blu-ray Disc Read Only Memory) playback apparatuses.
When a BD-ROM playback apparatus displays a text subtitle, the BD-ROM playback apparatus performs a control to develop codes constituting the subtitle into bitmaps representing fonts, and display the bitmaps in synchronization with each picture of the video stream.
This technique, with which subtitles can be created using code sequences, facilitates the creation of subtitles and makes it possible to create subtitles of such minority languages that have not been created conventionally. This widens the expression of subtitles and adds more values to the moving picture works.
A conventional technique for displaying text subtitles is disclosed in the following document:    Document 1: Japanese Patent Application Publication No. 2000-228656.